private void JoinNodesAtIndex(int index)
{
ExtentListNode node = list.ValueAt(index);
ExtentListNode?prevNode = null;
ExtentListNode?nextNode = null;
if (index - 1 >= 0)
{
prevNode = list.ValueAt(index - 1);
}
if (index + 1 < list.Count)
{
nextNode = list.ValueAt(index + 1);
}
//if any node is length 0, remove it
if (prevNode != null && prevNode.Value.Length == 0)
{
Remove(prevNode.Value);
return;
}
if (nextNode != null && nextNode.Value.Length == 0)
{
Remove(nextNode.Value);
return;
}
//see if we can join all three nodes together
if (prevNode != null && nextNode != null &&
node.Member == prevNode.Value.Member && node.Member == nextNode.Value.Member)
{
int totalSize = prevNode.Value.Length + node.Length + nextNode.Value.Length;
//if any node is a file-backed node
list.RemoveRangeAt(index - 1, 3);
Add(prevNode.Value.Start, totalSize, node.Member);
return;
}
//see if we can join previous node to middle node
if (prevNode != null && node.Member == prevNode.Value.Member)
{
int totalSize = prevNode.Value.Length + node.Length;
list.RemoveRangeAt(index - 1, 2);
Add(prevNode.Value.Start, totalSize, prevNode.Value.Member);
return;
}
//see if we can join next node to middle node
if (nextNode != null && node.Member == nextNode.Value.Member)
{
int totalSize = node.Length + nextNode.Value.Length;
list.RemoveRangeAt(index, 2);
Add(node.Start, totalSize, node.Member);
return;
}
}
private void Remove(ExtentListNode node)
{
list.Remove(node.Start);
}